diff --git a/backends/Makefile.objs b/backends/Makefile.objs
index 875eebc..8836761 100644
--- a/backends/Makefile.objs
+++ b/backends/Makefile.objs
@@ -1 +1,2 @@
-common-obj-y += rng.o rng-random.o rng-egd.o
+common-obj-y += rng.o rng-egd.o
+common-obj-$(CONFIG_POSIX) += rng-random.o